Switch trigger locking pin



. Jan. 19, 1960 R. J. OMARA 2,922,012

SWITCH TRIGGER LOCKING PIN Filed Nov. 22, 1957 N A z '4 I,

/.33 I I as .5 Q BY ATTORNEYS SWITCH TRIGGER LOCKING PIN Robert J.QMara, Liverpool, N.Y., assiguor to Pass & Seymour, incn, Syracuse,N.Y., a corporation of New York Application November 22, 1957, SerialNo. 698,139

3 Claims. (Cl. 200-157) This invention relates to locking pin assembliesand more particularly to locking pins arranged for use with triggerswitches.

It is a general object of the present invention to provide a novel andimproved locking pin assembly.

More particularly, it is an object of the present invention to provide alocking pin assembly the parts of which are all made with extremelysimple tools and do not require the use of so-called screw machineoperations or like practices, whereby the over-all cost is substantiallyreduced without in anywise reducing the efliciency, effectiveness orappearance of the article.

It is an important object of the present invention to provide a lockingpin assembly of the type used for maintaining a trigger switch in one ofits circuit controlling positions after it has been retracted by anoperator, and in which the parts and mounting means are simple sheetmetal parts and a solid rivet.

Other and further objects and features of the invention will be moreapparent to those skilled in the art upon consideration of theaccompanying drawing and following specification, wherein is disclosed asingle exemplary embodiment of the invention together with illustrationsof its use in connection with a trigger switch, it being understood thatsuch changes and modifications may be made therein as fall within thescope of the appended claims without departing from the spirit of theinvention.

In said drawings:

Fig. 1 is a side elevation of the pistol grip and trigger portion of amotorized tool, showing mounted beside the trigger a locking pinconstructed in accordance with the present invention for securing thetrigger in the retracted or circuit-closing position;

Fig. 2 is a side elevation on an enlarged scale of the trigger, itslocking pin and the associated switch for control by the trigger, whichswitch is housed within the handle shown in Fig. 1;

Fig. 3 is a top plan view of the showing of Fig. 2;

Fig. 4 is a horizontal section on an enlarged scaletaken on line 4-4 ofFig. 2- showing only the locking pin assembly;

Fig. 5 is a view of the rivet head end of the locking pin assembly takenon line 55 of Fig. 4;

Fig. 6 is plan of a sheet metal blank from which the guide sleeve isformed; and

Fig. 7 is a fragmentary view similar to Fig. 4 but showing the pin intrigger holding relationship.

In many industries there is a demand for a longitudinally reciprocable,spring-retracted locking pin of simple form and relatively small sizebut heretofore such devices have been of complex construction requiringthe use in the assembly of one or more so-called screw machine parts,i.e. parts made from solid rod or the like having sections of difierentdiameters achieved by the equivalent of turning operations in automaticscrew machines. Not only is this process wasteful of material, and manyof these locking pins must be of non-ferrous substances, but

nited States Patent i the time consumed and the expense involved makesthe mechanism too costly for many uses.

As an example may be mentioned the use of a locking I pin for thetrigger which operates the switch of a hand tool. It is highly desirablein small motor driven drills, saws and similar tools to be able to lockthe trigger in its retracted position so that the operator may put histrigger finger to better use in guiding the tool.

As an example of the use of such a locking pin reference may be had toFig. 1 of the drawing where 10 represents the motor of a portable powertool and 12 a handle adapted to be grasped by the user. At 13 is shown atrigger slidably mounted at the upper part of the handle and adapted,when retracted, to close the electric circuit from the cable 14 to themotor. The trigger is returned by a substantial spring, not shown, andto hold it for long periods of time becomes exceedingly tiresome andbesides the trigger finger may be put to better use in guiding the toolfor precise work. To lock the trigger in a retracted position there isprovided closely adjacent one side Wall of it a side rail mounting aplate 15 which supports a longitudinally slidable locking pin 16extending through the plate and headed there to be received in a hole inthe side wall of the trigger when the latter is in retracted position.The head then projects through the trigger side plate and if the latteris then released it retracts a small amount when the edge of the holetherein engages the locking pin, which latter may then be released sincethe inner edge of the head thereon engages the inner wall of the plateto prevent it from being withdrawn whereby it holds the trigger incircuit closing position.

To release the trigger it is only required to pull the trigger the smallamount necessary for the edge of the hole to clear the locking pin head,which is then withdrawn by its own spring so the trigger may be releasedto open the circuit.

Figs. 2 and 3 show the trigger 13 mounted for reciprocation throughcover plate 18 for actuating mechanism, not shown, within switch 20having terminals 21. The cover plate is provided with integral side rail21 from which plate 15, previously referred to, extends. It has aU-shaped sunken border 22 which substantially engages the contiguousflat wall 24 of the trigger to act as a guide and prevent lateralwobbling thereof. The trigger, as shown, may be a molded plastic part.

The main or raised portion of plate 15 provides clear ance for thoselocking pin assembly parts which extend onto the trigger side of plate15 as disclosed in Figs. 4 and 5. In the side wall 24 of the trigger isopening 25 which in the extended or normal position of the trigger isspaced as shown in respect to the locking pin axis assembly thereon, asseen in Fig. 4. When the trigger is pulled to close the circuit it movesdownward as seen in Fig. 4 until the opening 25 is aligned with thecenter of the locking pin so that the latter may be projected by thumbpressure into this opening to lock the trigger in the On position.

For a better understanding of the locking pin construction reference ishad to Figs. 3, 4, 5 and 6 where the assembly includes side plate 15,cylindrical sleeve 26 secured thereto in coaxial arrangement with thecircular hole 27, eyelet or tube 28 arranged in telescopic relation toand for guidance by sleeve 26, solid rivet 29 extending through the hole27, headed on the trigger side of the plate 15 as at 30 and having itsupper end riveted over as at 31 after passing through a central aperturein the partially closed end 32 of eyelet 28.

The spaced-coil helical spring 33 surrounds the shank of the long rivetand bears at one end on the annular area of plate 15 within the sleeve26 and at its other on portion 32 of eyelet 28 and exerts sufl'icientpressure to maintain blank is curled into a cylinder with ends 38abutting as seen in Fig. 3,. Tabs 37 are extended throughcircumferential slots 38 arranged about and spaced from the periphery ofhole 27 in plate 15 through which the rivet passes. Thus when assembledand with the tabs turned outwardly as clearly illustrated in Fig. 4, thesleeve 26 is positioned normal to the face of plate 35 and coaxial withhole 27 therein.

Rivet 29 has a long straight shank sized to be guided in hole 27 forsliding movement. 'Head 30 is upset thereon in the usual manner and isof somewhat greater diameter than hole 27 to remain positioned; on thetrigger side of plate 15. After it has been so positioned its shank issurrounded by the coils of spring 33.

The eyelet or tube 28 may either be made by curling up a fiat plate intoa cylinder, as in the case of sleeve 26, and turning in end 32 or thewhole thing may be drawn or stamped in a single operation withexceedingly vsimple dies. This permits a better centering of the holewhich receives the reduced diameter end of therivet, which may beeffected by a rolling operation requiring no cutting. This end'isprovided'with central hole 40 tubularizing it to facilitate theupsetting operation, shown at 31, after the eyelet has been assembledover it and the upper end of the spring and is telescoped into thesleeve 26. This completes the assembly and holds the parts with theinner end of the eyelet spaced from plate 15 a distance greater thanthat necessary for movement to project head 3% through the trigger wallto assume the position illustrated in Fig. 7 when the triggeris pulledand then locked. Here the hole 25 in the wall 24 of the trigger has beendrawn down, first a suflicient distance to be substantially concentricwith head 30 of rivet 29 which is then projected through opening 25while holding the trigger retracted. After the rivet passes throughopening 25 the. trigger is released and on tending to be returned by itsspring the lower Wall of opening 25 engages the rivet shank with aportion of the rivet head 3% overhanging the inner face of trigger wall24 preventing spring 33 from retracting the locking pin, and holding thetrigger in its pulled. position. To release the locking pin from thetrigger the latter is pulled slightly to separate the inner face of wall24 from overhang, when the retractile spring for the locking pinwithdraws the same and the trigger can then be released to open theswitch.

It will be seen that the locking pin assembly is constructed wholly ofparts which do not require any machine operations in the nature ofturning or the like, and

that all of the parts are made either by simple stamping or upsettingoperations from flat sheet metal and straight rod. Under thesecircumstances the cost is materially reduced and the time of manufactureand assembly substantially shortened. At the same time the price is keptextremely low.

Having thus described my invention, what I claim as novel and desire tosecure by Letters Patent of the United States is:

l. A spring retracted locking pin assembly mounted on a sheet metalplate having a hole therein comprising in combination a straight walled,rolled, cylindrical sleeve having integral tabs at one end extendingthrough openings located in said plate to position the sleeve coaxialwith said hole and spaced outwardly from the edges thereof, a straightwalled, sheet-metal eyelet telescoped with said sleeve and having itsfree end turned inwardly to leave a central opening, open coil helicalspring having one end abutting saidplate within the sleeve and the otherend within the eyelet and abutting said free end, an elongated solidrivet sized to slide loosely in the hole in said plate and through saidspring, a head on said rivet larger than said hole normally abutting theplate on the side opposite said sleeve, the remote end of the rivethaving a rolled shoulder abutting the turned in end of the eyelet and aportion extending through the center thereof and riveted over to holdthe parts assembled.

2. A self-retracting locking pin assembly for mounting on a thin platehaving a hole therein and a plurality of slots spaced outwardly from theperiphery thereof, a rectangular sheet of metal having tabs extendingfrom one long edge thereof and sized to each fit one'of said slots, saidstrip being curled into a cylindrical sleeve larger in diameter thansaidhole and having'said tabs extending through said slots and bent overbeneath the plate, a solid rivet sized to and extending freely throughsaid hole and having a head normally abutting the plate about the holeperiphery on the opposite side from the sleeve, a helical spring of theopen coil type loosely surrounding the rivet and having one end abuttingthe plate withinthe sleeve, a tube telescoping with said sleeveandspringand being shorter than said rivet, said tube having its outer end atleast partially closed and abutting and compressing said spring, andmeans securing the said outer end of the tube and the outer end of therivet together to hold the parts assembled.

3. The assembly as defined in claim 2 in which said plate has an areaoffset from its general plane in the direction of said sleeve a distanceno less than the thickness of said rivet head, said areaincludingsaid-hole and slots.

References Cited in the file of this patent UNITED STATES PATENTS

